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/* nes_ntsc 0.2.2. http://www.slack.net/~ant/ */
#include "nes_ntsc.h"
/* Copyright (C) 2006-2007 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
nes_ntsc_setup_t const nes_ntsc_monochrome = { 0,-1, 0, 0,.2, 0,.2,-.2,-.2,-1, 1, 0, 0, 0, 0 };
nes_ntsc_setup_t const nes_ntsc_composite = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0 };
nes_ntsc_setup_t const nes_ntsc_svideo = { 0, 0, 0, 0,.2, 0,.2, -1, -1, 0, 1, 0, 0, 0, 0 };
nes_ntsc_setup_t const nes_ntsc_rgb = { 0, 0, 0, 0,.2, 0,.7, -1, -1,-1, 1, 0, 0, 0, 0 };
#define alignment_count 3
#define burst_count 3
#define rescale_in 8
#define rescale_out 7
#define artifacts_mid 1.0f
#define fringing_mid 1.0f
#define std_decoder_hue -15
#define STD_HUE_CONDITION( setup ) !(setup->base_palette || setup->palette)
#include "nes_ntsc_impl.h"
/* 3 input pixels -> 8 composite samples */
pixel_info_t const nes_ntsc_pixels [alignment_count] = {
{ PIXEL_OFFSET( -4, -9 ), { 1, 1, .6667f, 0 } },
{ PIXEL_OFFSET( -2, -7 ), { .3333f, 1, 1, .3333f } },
{ PIXEL_OFFSET( 0, -5 ), { 0, .6667f, 1, 1 } },
};
static void merge_kernel_fields( nes_ntsc_rgb_t* io )
{
int n;
for ( n = burst_size; n; --n )
{
nes_ntsc_rgb_t p0 = io [burst_size * 0] + rgb_bias;
nes_ntsc_rgb_t p1 = io [burst_size * 1] + rgb_bias;
nes_ntsc_rgb_t p2 = io [burst_size * 2] + rgb_bias;
/* merge colors without losing precision */
io [burst_size * 0] =
((p0 + p1 - ((p0 ^ p1) & nes_ntsc_rgb_builder)) >> 1) - rgb_bias;
io [burst_size * 1] =
((p1 + p2 - ((p1 ^ p2) & nes_ntsc_rgb_builder)) >> 1) - rgb_bias;
io [burst_size * 2] =
((p2 + p0 - ((p2 ^ p0) & nes_ntsc_rgb_builder)) >> 1) - rgb_bias;
++io;
}
}
static void correct_errors( nes_ntsc_rgb_t color, nes_ntsc_rgb_t* out )
{
int n;
for ( n = burst_count; n; --n )
{
unsigned i;
for ( i = 0; i < rgb_kernel_size / 2; i++ )
{
nes_ntsc_rgb_t error = color -
out [i ] - out [(i+12)%14+14] - out [(i+10)%14+28] -
out [i + 7] - out [i + 5 +14] - out [i + 3 +28];
DISTRIBUTE_ERROR( i+3+28, i+5+14, i+7 );
}
out += alignment_count * rgb_kernel_size;
}
}
void nes_ntsc_init( nes_ntsc_t* ntsc, nes_ntsc_setup_t const* setup )
{
int merge_fields;
int entry;
init_t impl;
float gamma_factor;
if ( !setup )
setup = &nes_ntsc_composite;
init( &impl, setup );
/* setup fast gamma */
{
float gamma = (float) setup->gamma * -0.5f;
if ( STD_HUE_CONDITION( setup ) )
gamma += 0.1333f;
gamma_factor = (float) pow( (float) fabs( gamma ), 0.73f );
if ( gamma < 0 )
gamma_factor = -gamma_factor;
}
merge_fields = setup->merge_fields;
if ( setup->artifacts <= -1 && setup->fringing <= -1 )
merge_fields = 1;
for ( entry = 0; entry < nes_ntsc_palette_size; entry++ )
{
/* Base 64-color generation */
static float const lo_levels [4] = { -0.12f, 0.00f, 0.31f, 0.72f };
static float const hi_levels [4] = { 0.40f, 0.68f, 1.00f, 1.00f };
int level = entry >> 4 & 0x03;
float lo = lo_levels [level];
float hi = hi_levels [level];
int color = entry & 0x0F;
if ( color == 0 )
lo = hi;
if ( color == 0x0D )
hi = lo;
if ( color > 0x0D )
hi = lo = 0.0f;
{
/* phases [i] = cos( i * PI / 6 ) */
static float const phases [0x10 + 3] = {
-1.0f, -0.866025f, -0.5f, 0.0f, 0.5f, 0.866025f,
1.0f, 0.866025f, 0.5f, 0.0f, -0.5f, -0.866025f,
-1.0f, -0.866025f, -0.5f, 0.0f, 0.5f, 0.866025f,
1.0f
};
#define TO_ANGLE_SIN( color ) phases [color]
#define TO_ANGLE_COS( color ) phases [(color) + 3]
/* Convert raw waveform to YIQ */
float sat = (hi - lo) * 0.5f;
float i = TO_ANGLE_SIN( color ) * sat;
float q = TO_ANGLE_COS( color ) * sat;
float y = (hi + lo) * 0.5f;
/* Optionally use base palette instead */
if ( setup->base_palette )
{
unsigned char const* in = &setup->base_palette [(entry & 0x3F) * 3];
static float const to_float = 1.0f / 0xFF;
float r = to_float * in [0];
float g = to_float * in [1];
float b = to_float * in [2];
q = RGB_TO_YIQ( r, g, b, y, i );
}
/* Apply color emphasis */
#ifdef NES_NTSC_EMPHASIS
{
int tint = entry >> 6 & 7;
if ( tint && color <= 0x0D )
{
static float const atten_mul = 0.79399f;
static float const atten_sub = 0.0782838f;
if ( tint == 7 )
{
y = y * (atten_mul * 1.13f) - (atten_sub * 1.13f);
}
else
{
static unsigned char const tints [8] = { 0, 6, 10, 8, 2, 4, 0, 0 };
int const tint_color = tints [tint];
float sat = hi * (0.5f - atten_mul * 0.5f) + atten_sub * 0.5f;
y -= sat * 0.5f;
if ( tint >= 3 && tint != 4 )
{
/* combined tint bits */
sat *= 0.6f;
y -= sat;
}
i += TO_ANGLE_SIN( tint_color ) * sat;
q += TO_ANGLE_COS( tint_color ) * sat;
}
}
}
#endif
/* Optionally use palette instead */
if ( setup->palette )
{
unsigned char const* in = &setup->palette [entry * 3];
static float const to_float = 1.0f / 0xFF;
float r = to_float * in [0];
float g = to_float * in [1];
float b = to_float * in [2];
q = RGB_TO_YIQ( r, g, b, y, i );
}
/* Apply brightness, contrast, and gamma */
y *= (float) setup->contrast * 0.5f + 1;
/* adjustment reduces error when using input palette */
y += (float) setup->brightness * 0.5f - 0.5f / 256;
{
float r, g, b = YIQ_TO_RGB( y, i, q, default_decoder, float, r, g );
/* fast approximation of n = pow( n, gamma ) */
r = (r * gamma_factor - gamma_factor) * r + r;
g = (g * gamma_factor - gamma_factor) * g + g;
b = (b * gamma_factor - gamma_factor) * b + b;
q = RGB_TO_YIQ( r, g, b, y, i );
}
i *= rgb_unit;
q *= rgb_unit;
y *= rgb_unit;
y += rgb_offset;
/* Generate kernel */
{
int r, g, b = YIQ_TO_RGB( y, i, q, impl.to_rgb, int, r, g );
/* blue tends to overflow, so clamp it */
nes_ntsc_rgb_t rgb = PACK_RGB( r, g, (b < 0x3E0 ? b: 0x3E0) );
if ( setup->palette_out )
RGB_PALETTE_OUT( rgb, &setup->palette_out [entry * 3] );
if ( ntsc )
{
nes_ntsc_rgb_t* kernel = ntsc->table [entry];
gen_kernel( &impl, y, i, q, kernel );
if ( merge_fields )
merge_kernel_fields( kernel );
correct_errors( rgb, kernel );
}
}
}
}
}
#ifndef NES_NTSC_NO_BLITTERS
void nes_ntsc_blit( nes_ntsc_t const* ntsc, NES_NTSC_IN_T const* input, long in_row_width,
int burst_phase, int in_width, int in_height, void* rgb_out, long out_pitch )
{
int chunk_count = (in_width - 1) / nes_ntsc_in_chunk;
for ( ; in_height; --in_height )
{
NES_NTSC_IN_T const* line_in = input;
NES_NTSC_BEGIN_ROW( ntsc, burst_phase,
nes_ntsc_black, nes_ntsc_black, NES_NTSC_ADJ_IN( *line_in ) );
nes_ntsc_out_t* restrict line_out = (nes_ntsc_out_t*) rgb_out;
int n;
++line_in;
for ( n = chunk_count; n; --n )
{
/* order of input and output pixels must not be altered */
NES_NTSC_COLOR_IN( 0, NES_NTSC_ADJ_IN( line_in [0] ) );
NES_NTSC_RGB_OUT( 0, line_out [0], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 1, line_out [1], NES_NTSC_OUT_DEPTH );
NES_NTSC_COLOR_IN( 1, NES_NTSC_ADJ_IN( line_in [1] ) );
NES_NTSC_RGB_OUT( 2, line_out [2], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 3, line_out [3], NES_NTSC_OUT_DEPTH );
NES_NTSC_COLOR_IN( 2, NES_NTSC_ADJ_IN( line_in [2] ) );
NES_NTSC_RGB_OUT( 4, line_out [4], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 5, line_out [5], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 6, line_out [6], NES_NTSC_OUT_DEPTH );
line_in += 3;
line_out += 7;
}
/* finish final pixels */
NES_NTSC_COLOR_IN( 0, nes_ntsc_black );
NES_NTSC_RGB_OUT( 0, line_out [0], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 1, line_out [1], NES_NTSC_OUT_DEPTH );
NES_NTSC_COLOR_IN( 1, nes_ntsc_black );
NES_NTSC_RGB_OUT( 2, line_out [2], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 3, line_out [3], NES_NTSC_OUT_DEPTH );
NES_NTSC_COLOR_IN( 2, nes_ntsc_black );
NES_NTSC_RGB_OUT( 4, line_out [4], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 5, line_out [5], NES_NTSC_OUT_DEPTH );
NES_NTSC_RGB_OUT( 6, line_out [6], NES_NTSC_OUT_DEPTH );
burst_phase = (burst_phase + 1) % nes_ntsc_burst_count;
input += in_row_width;
rgb_out = (char*) rgb_out + out_pitch;
}
}
#endif
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